diff options
author | Paul Eggert <eggert@cs.ucla.edu> | 2011-06-30 15:14:25 -0700 |
---|---|---|
committer | Paul Eggert <eggert@cs.ucla.edu> | 2011-06-30 15:24:37 -0700 |
commit | 2deeabadbd2d7eaebc49d62f818e60f40159b0ff (patch) | |
tree | 10c2a804cb42e51a52e70a76af8462a636774627 /lib/dtotimespec.c | |
parent | 1a37ff9e61f483132e7734f929e6675b1651a647 (diff) | |
download | gnulib-2deeabadbd2d7eaebc49d62f818e60f40159b0ff.tar.gz |
dtotimespec: new module
* lib/timespec.h (dtotimespec): New decl.
* lib/dtotimespec.c, modules/dtotimespec: New files.
Diffstat (limited to 'lib/dtotimespec.c')
-rw-r--r-- | lib/dtotimespec.c | 69 |
1 files changed, 69 insertions, 0 deletions
diff --git a/lib/dtotimespec.c b/lib/dtotimespec.c new file mode 100644 index 0000000000..ea0470a785 --- /dev/null +++ b/lib/dtotimespec.c @@ -0,0 +1,69 @@ +/* Convert double to timespec. + + Copyright (C) 2011 Free Software Foundation, Inc. + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. */ + +/* written by Paul Eggert */ + +/* Convert the double value SEC to a struct timespec. Round toward + positive infinity. On overflow, return an extremal value. */ + +#include <config.h> + +#include "timespec.h" + +#include "intprops.h" + +struct timespec +dtotimespec (double sec) +{ + enum { BILLION = 1000 * 1000 * 1000 }; + double min_representable = TYPE_MINIMUM (time_t); + double max_representable = + ((TYPE_MAXIMUM (time_t) * (double) BILLION + (BILLION - 1)) + / BILLION); + struct timespec r; + + if (! (min_representable < sec)) + { + r.tv_sec = TYPE_MINIMUM (time_t); + r.tv_nsec = 0; + } + else if (! (sec < max_representable)) + { + r.tv_sec = TYPE_MAXIMUM (time_t); + r.tv_nsec = BILLION - 1; + } + else + { + time_t s = sec; + double frac = BILLION * (sec - s); + long ns = frac; + ns += ns < frac; + s += ns / BILLION; + ns %= BILLION; + + if (ns < 0) + { + s--; + ns += BILLION; + } + + r.tv_sec = s; + r.tv_nsec = ns; + } + + return r; +} |